克罗恩病患者回肠末端M细胞的超微结构变化

Ultrastructural changes of M cell in terminal ileum of patients with Crohn's disease

目的了解克罗恩病早期的细胞学改变,揭示其可能的发病机制。方法克罗恩病患者7例,女4例,男3例,年龄16-49(平均24.5)岁,符合1993年6月太原会议《全国慢性非感染性肠病研讨会》制定的诊断标准。正常对照组16例,女8例,男8例,年龄18～69(平均29.5)岁。结肠镜检查时从末端回肠活检淋巴滤泡增生样组织,应用扫描电镜,透射电镜观察淋巴滤泡相关上皮中M细胞所占比例及其病理改变。结果克罗恩病组M细胞在淋巴滤泡相关上皮中所占比例(16％)显著高于正常对照组(2.4％,P<0.01),克罗恩病组M细胞在相邻上皮细胞无病理改变的情况下出现破裂,淋巴细胞由此突入肠腔。结论淋巴滤泡顶部M细胞的破裂导致肠粘膜上皮层的破坏,肠腔内容物可能由此进入肠粘膜淋巴组织,这种病理机制可能会导致肠粘膜阿弗他溃疡形成。

AIM To better understand the initial cellular events and to reveal the possible pathogenetic mechanisms of Crohns dlsease. METHODS Mucosal biopsies were taken from terminal ileum of 8 patients with Crohn's disease and 16 controls through colonoscopy, the changes of M cells were examined under scanning electron microscopy and transmission electron microscopy. RESULTS The percentage of M cells in the follicleassociated epithelium was significantly increased in patients with Crohn's disease (16%) as compared with that of control group(2.4%). Disruption of M cell was observed in Crohn's disease. Lymphocytes projecting to the gut lumen at the site of damaged M cell. There were no obvious alterations of enterocytes next to the bursting M cell. CONCLUSION The rupture of M cells may be the earliest lesion in Crohn's disease, the bursting of M cells at the top of the lymphoid follicles breaking up epithelial barriers and facilitating the pathogen and antigens in the gut lumen entering into the lymphoid tissue of intestinal mucosa, which may induce the local immune reaction and then lead to aphthold ulcers.